484 Scientific Proceedings, Royal Dublin Society. 



Goat 3. 



1. deduction in daily ration (change from ration A to B) produces — 



(a) No change in milk yield. 



(5) Eeduction in daily per cent, fat of 0-75 (4-0 to 3-25). 

 (c) Eeduction in daily total fat of 0'02 lb. (0175 to 0-150). 



2. Addition of 0'5 lb. butter fat to ration (change from ration B to C) 

 produces — 



(a) No change in milk yield. 



(h) Increase in daily per cent, fat of I'D (3'25 to 4'25). 



(c) Increase in daily total fat of 0-04 lb. (0-15 to 0-19). 



3. Addition of 1'13 lbs. casein to daily ration (change from ration E to F) 

 produces — 



(a) No change in total milk yield. 



(6) Increase in daily per cent, fat of 0'75 (4'5 to 5'25). 



(c) Increase in daily total fat of 0-025 lb. (0-110 to 0-135). 



4. Further addition of 0'5 lb. fat to daily ration (change from ration 

 F to G) produces— 



(ft) No change in milk. 



(5) Increase in daily per cent, fat of 1-0 (5-25 to 6-25). 



(c) Increase in daily total fat of 0-025 lb. (0-135 to 0-160). 



5. Eeduction in daily ration (change from ration G to H) produces — 



(a) No change in milk yield. 



(6) Eeduction in d-aily per cent, fat of 1-5 (6-25 to 4-75). 

 (c) Eeduction in daily total fat. 



The foregoing results lead to the following conclusions : — 



1. By considerably reducing the ration the total daily yield of fat is 

 reduced. If, at the same time, there is little or no reduction in milk yield, 

 the percentage of fat in the milk is lowered. This occurs in the early stages 

 of lactation, when the mammary gland is very active, and towards the end 

 of the lactation, when the milk flow is already reduced to a minimum. 

 Obviously, a fall in milk yield, accompanied by a fall in total fat, may leave 

 the percentage of fat unchanged ; and conceivably a considerable fall in millc 

 occurring at the same time as a reduction in total fat may produce .an 

 increase in the percentage of fat in the milk. 



